1. Technical Field
The present invention relates to an image processing apparatus, a projector, an image processing method, and a program, and more particularly to an image processing apparatus which can increase sharpness at an edge portion of an image projected by a projector, an image processing method, a projector, and a program.
2. Related Art
In general, projectors have been used in which light incident from a light source based on image information is modulated by light modulating means such as a liquid crystal panel, and the modulated light is focused on a screen using a projection optical system to thereby display an image. In such projectors, the distance from the projection optical system to the screen is different at the center of the projected image from that it is at an outer edge portion of the projected image. Therefore, when the center of the projected image is focused, the edge portion is not focused, leading to a problem that the image has poor sharpness.
Therefore, a technique has been disclosed in which, for example, the distance between the projector and the screen is measured using an ultrasonic range finder, and a projector lens is automatically focused to thereby perform a focus adjustment (refer to JP-A-4-338706, for example). As another related art, a technique has been disclosed in which, for example, by appropriately increasing or decreasing the inclination angle of an optical modulation device and using a focus-checking pattern projected on the entire screen, the adjustment can be made so that even the upper and lower edges of the screen are focused (refer to JP-A-2006-352514, for example).
In the technique described in JP-A-4-338706, however, although the vicinity of the optical axis of the screen is focused, the edge portion of the projected area is still not focused, leading to a problem that the image has poor sharpness. In the technique described in JP-A-2006-352514, although the entire area of the screen can be focused to certain extent, the structure is extremely complicated, leading to problems that the manufacturing is difficult, and the manufacturing cost is high.